Anyone who wants to open a massage parlor in San Francisco would first have to meet their future neighbors at a public hearing, under proposed rules intended to weed out spas that serve as fronts for brothels.

The Board of Supervisors will vote on the proposal Tuesday. It's part of an effort by city leaders to curb the illegal sex trade in San Francisco, part of the growing $8 billion international sex trafficking industry.

"My ordinance is aimed at immigrant women who are here working in the massage parlors against their will," said Supervisor Fiona Ma, a candidate for state Assembly who introduced her idea shortly after federal agents raided 10 Asian massage parlors in San Francisco in summer 2005.

A recent series in The Chronicle reported that scores of Asian massage parlors in San Francisco offer sex, and that some of the women inside are forced to work against their will. During last year's raid, federal agents arrested 29 people for alleged ties to a South Korean sex trafficking ring and removed 104 Korean masseuses in California's largest sex trafficking bust.

Ma wants to put "conditional use" restrictions on massage parlor permits so that neighbors living within 300 feet of a proposed spa would be invited to air any concerns in a public hearing.

Applicants would also need approval from the planning commission before they could request a massage parlor permit from the Department of Public Health.

Mayor Gavin Newsom has said public hearings are a good idea, and Ma says she believes she has at least five of the 10 other supervisors on her side.

"The revelations that young women were being used as sex slaves at some of these businesses was a shock to me and the city," said Supervisor Gerardo Sandoval, a co-sponsor of Ma's legislation. "We should be especially careful about granting permits to these types of businesses."

But not everyone likes the idea.

Supervisor Jake McGoldrick is concerned that legitimate massage providers and women who are willing sex workers will be unduly punished by a rush to legislate parlors.

"Let's take a look and figure out what's exploitation and what's not and what we can do to make it safer for the folks who are working in consensual, contractual arrangements," he said.

Norma Hotaling, who advocates for trafficked women as the director of the SAGE Project in San Francisco, is also against public hearings for massage parlors, but for very different reasons.

"I don't think it should be up to the public to get themselves to meetings to serve as the watchdogs. The police and city leaders should be enforcing anti-pimping laws already on the books," she said.

A second Ma proposal, to impose a one-year moratorium on all new massage parlors in San Francisco to give city officials time to revoke permits of spas that sell sex, will be considered by the board next month.

"The topic of massage parlors always brings a big debate about prostitution," Ma said. "But people forget about the victims -- those who are not coming to our offices or to City Hall to complain. They need voices to speak up for them."